Fundus camera imaging is acknowledged to be an important diagnostic tool for detection of various conditions affecting the eye, including diabetic retinopathy and macular degeneration. Various embodiments of fundus imaging apparatus are disclosed, for example in U.S. Pat. Nos. 5,713,047 (Kohayakawa); 5,943,116 (Zeimer); 5,572,266 (Ohtsuka); 4,838,680 (Nunokawa); 6,546,198 (Ohtsuka); and 6,636,696 (Saito).
While conventional fundus imaging apparatus require manual operation, there has been considerable effort expended toward automating specific functions of these imaging apparatus. For example, U.S. Pat. No. 6,296,358 (Cornsweet et al.) discloses an automated sequence that is executed for pupil alignment and focusing. U.S. Pat. No. 4,732,466 (Humphrey) discloses an automated focus mechanism for a fundus imaging apparatus. U.S. Pat. No. 6,733,129 (Masaki) discloses an automatic alignment sequence using a feedback loop with a light beam projected onto the cornea, a sensor for sensing reflected light, and a series of motors for effecting alignment adjustment. U.S. Pat. No. 6,705,726 (Tanassi et al.) discloses a multi-function optical imaging apparatus with a number of automation features in various subsystems. U.S. Pat. No. 6,830,336 (Fransen) discloses automation of the sequencing of images for a patient, in order to obtain a complete series of fundus images once the patient is properly positioned and suitable focus has been achieved.
While these patents attest to continuous improvements in fundus camera design, there are still significant hurdles to widespread acceptance and usability of these devices. Among disadvantages noted with current apparatus are relative complexity of operation. This remains the case even with improvements that automate focus and alignment operations, as noted above.
A number of fundus imaging apparatus are designed for the more limited function of diabetic retinopathy screening. These devices are intended to be used by relatively unskilled operators who receive minimal training. For example, these lower cost fundus imaging apparatus are intended to be installed at a personal care physician (PCP) office or in medical test lab collection facility, rather than at a specialist's facility. The intent is to have these apparatus operated by a clerical staff of medical technicians at the PCP office of other site, to obtain images for first-level screening. In order to provide simple operation, these fundus imaging apparatus are designed with an operator interface that provides controls for operation, with operator feedback as well as automated response to events such as patient head and eye movement.
While recent designs appear to offer better usability and performance of these systems, however, there remains considerable room for improvement. One inherent problem relates to the operator learning curve. While a number of these systems offer ease of operation, they still require some amount of practice. An operator working with a fundus imaging apparatus can achieve some facility after working continuously with such a system for an hour or so, particularly under trained guidance. However, only a small percentage of patients in the PCP environment will require this type of screening. Operating this equipment once or twice a day may not give an operator enough practice to achieve a level of mastery of the apparatus. Moreover, problems of staff scheduling and turnover may make it impractical for a facility to have only a single staff member trained to use this apparatus. Thus, even though newer fundus imaging apparatus may be easier to operate, there are inherent barriers to taking advantage of easier operation. In order to be economical, classroom or individual training is impractical. Instead, operator training must be delivered in electronic form, such as by CD or over the Internet, or by means of a manual or quick-reference guide. Even using on-screen prompts, it would be very difficult to provide effective interactive operator assistance during imaging.
There is a need for an improved fundus imaging apparatus that is essentially operable without operator intervention. This would make it possible, for example, to have an imaging system that is automated or is even operable by patients themselves, with minimal setup instruction from PCP staff members.